Lifting-jack.



H. J. SCHMICK.

LIFIING JACK.

APPLICATION mu) AUG.I4. 1916.

3 SHEETSSHEET 1- Swumboz Y H. J. SCHMICK.

LIFHNG JACK.

APPLICATION FILED AUG-14.1913.

1,245,622 Patented Nov. 6, 1917. 3 SHEETSSHEET 2.

awe/14 5M H. J. SCHMICK.

LIFTING JACK.

APPLICATION flLED Aua.l4. I916.

Patented Nov. 6, 1917.

' 3 SHEETS-SHEET 3- iv lmmlllllli a -lllllllllll lifting jacks.

HENRY J. SGHlVlIIGK, or LOCK HAVEN, PENNSYLVANIA.

LIFTING-J'ACK.

Specification of Letters Patent.

Application filed August 14, 1916. Serial No. 114,806.

To all whom it may concern:

Be it known that I, HENRY J. SCHMICK, a

citizen of the United States, residing at Lock Haven, in the county of Clinton and State of Pennsylvania, haveinvented certain newand useful Improvements in Lifting-Jacks; andIdohereby declare the following to be a full, clear, and exact description. of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention relates to improvements in The primary object of the invention is to provide a device of the character mentioned, and one of a comparatively inexpensive and extremely simplified construction.

Another object of the invention is to provide, a device of this character, and one in which maximum power is applied to the load to be lifted with a minimum amount of power for the operation of the same, and without, sacrificing time, such as has not heretofore obtained in the art.

A further object ofv the invention is tov provide adevice of the character mentioned and one in which the weight of the load being raised is sustained at any desired point within the range of the same without resorting to the use of. additional or extraneous mechanisms, such as pawls or the like, as has heretofore obtained in the known types of such devices.

Vith these and other objects in view, the invention relates to the certain new and useful construction as will be hereinafter more fully described, set forth in the appended claims, and illustrated in the accompanying drawings, in which Figure 1 is a front elevation of the device, Fig. 2 is a side elevation, Fig. 3 is a side elevation partly in section, Fig. a is an elevation of the cam operatmechanism,

ig. 5 is a horizontal transverse section on the line 55 of Fig. 4,

Fig. 6 is a plan view of the cam-gear and its actuating pinion as positioned on the inner wall of the removable face plate of the housing,

Fig. 7 is a fragmentary detail of the main drive gear.

Referringto the accompanying drawings in which similar characters of reference designate corresponding parts in the several views thereof, the numeral 10 indicates a hollow standard, risingfrom' abase plate 11, and having a housing'12. offset from the upper end thereof. Slidably mounted in the standard 10 is a lifting-bar 13,, which is Patented Nov. 6, 1917.

formed with a foot portion 14: at its lower end, the same normally, occupying a recess 15 formed in the upper face of the base plate 11, and a load supporting head 16 at its upper end. .Y

The inner vertical face of the lifting bar is arranged in the form of a rack 17, which is CO-BXlJQIlSlVG withthe major portion of the same. Extending transversely of the housing 12, and journaled in the opposite side walls thereof, is a relatively heavy shaft 18 on which is secured a small spur gear 19 in meshed engagement with the rack face 17, of the lifting bar. Immediately adjacent the small gear 19 and secured to the shaft 18 is a toothed gear 20, the same bein of relatively greater diameter than the first mentioned gear. 7

The housing 12 is provided with a removable side wall portion 21, in which is journaled one end of the shaft 18, and a removable front wall portion 22, by means of which the parts may be readily assembled or taken down when necessary. The removable side wall 21, of the housing, is formed with an offset front portion 23 for the purpose to be hereinafter set forth. The removable front wall 22, of the housing, is in i the form of integral circular portions 24c second stub shaft 33 j ournaled in the bearing extension 27. The outer or projected end 3%, of the shaft 33, is squared in a manner similar to that the projected end 29, of the shaft or spindle 23, for the reception of a suitable operating crank or handle (not shown). YVith the crank or handle engaged on the squared end 29, of the cam-shaft 28, great rapidity with less power is obtained in the operation of the lifting bar, and with the squared end 3 of the shaft 33, engaged and operated by the crank or handle, the speed of operation is reduced and the lifting power increased proportionately. This increase and decrease in speed of operation and lifting power may be varied throughout a wide range by varying the ratio of the gear 32 with respect to the cam-gear, which ratio, in the present instance, is about t to 1.

The cam-gear 30 when properly positioned within the housing 12, is disposed in a vertical plane and at right angles to the gear 20, and has its inner face formed with a single radio-helical cam-member 35, adapted to continually and progressively mesh with the radial curved teeth 36, of the gear 20. To effect the continuous engagement and progressive meshing of the working surfaces of the cam-element 35 with the radial teeth 36, of the gear 20, the said surfaces are disposed on a curve of approximate cycloidal formation, and are made angular in transverse section in one direction of the element forwardly from the inner starting point to a point approximately intermediate its length, and in a reverse angular or inclined relation for the remainder of its length to its outer end. This angularity of the cam-member or element 35, inclining first in one direction and then in a direction opposite thereto, causes the member to support the weight on the jack at any point in the travel of the lifting bar 13 through the medium of the radial teeth 36, of the gear, in engagement therewith, and dispenses with any and all of the usual clutch or stop mechanisms, heretofore provided for the purpose. The cam-member or element 35, as shown, is formed of a length to provide overlapping ends, so that two of the radial teeth 36, of the gear 20, are in constant engagement, and the space between the overlapped ends of the member 35 is of just sufficient greater width than that of a single tooth 36 to allow clearance of the same to and from engagement therewith, and in the revolution of the cam, the several teeth 36 are engaged consecutively.

To properly distinguish the approximate cycloidal curvature of the cam-element 35, the same has been designated radio-helical, since the motion defined by the travel of the member is radially or transaxially, and at right angles to the axis of the body 30,

and its direction of operation, in the present instance, is clock-wise or right handed.

Having thus described the embodiment of the invention, it is to be thoroughly understood that various changes in the detailed construction and arrangement may be resorted to without departing from the spirit and scope of the same.

Having thus fully described the invention, what is claimed, is

1. In a lifting ack, the combination of a standard, a lifting bar having a rack and moving vertically of said standard, a shaft journaled in the standard, a pinion mounted on the shaft and meshing with the rack, a revolnble member having a radio-helical'ca-in disposed on one face thereof, a gear wheel mounted on the shaft, the teeth of the gear being radial and engaging the radio-helical cam, the opposite faces of said teeth being similar and the opposite corners of the opposite faces of the teeth being disposed in alinement and parallel with a line drawn longitudinally through the axis of said gear wheel, the gear wheel being disposed at right angles to the revoluble member and one face thereof being substantially in alinement with the axis of the revoluble member, whereby the cam engages the whole side surfaces of the teeth and exerts its force at right angles to the axis of the gear when rotating same.

2. In a lifting jack, the combination of a standard, a lifting bar having a rack and 'movably mounted in the standard, a shaft journaled in the standard, a gear wheel on the opposite end of the shaft, the teeth of the gear wheel being radially disposed, one surface of each tooth being concaved and the opposite surface being convex to form curved spaces between the teeth, a cam shaft square at one end and carrying a gear at the op posite end and mounted in the standard at right angles to the first mentioned shaft, the axis of the cam shaft being in substantial alinement with one face of the gear wheel 011 the first mentioned shaft, a radio-helical cam projecting from one face of the gear on the cam shaft and meshing with the first mentioned gear, the walls of the cam being formed to engage the respective curved and convex surfaces of the teeth on the first mentioned gear whenever the cam is in engagement, and the face of the cam being irregularly concave to engage the base of each curved space between the teeth when in meshing relation, a stub shaft square at one end and carrying a pinion at its opposite end and mounted in the standard, the pinion meshing with the gear on the cam shaft.

3. In a lifting jack, the combination of a standard, a lifting bar having a rack and moving vertically of said standard, a shaft journaled in the standard, a pinion mounted on the shaft and meshing with the rack, a

revoluble member having a radio-helical cam disposed on one face thereof, the Walls of the cam being formed to engage radial teeth of a ear Wheel, a gear wheel mounted on the shaft, said gear Wheel having radial teeth which engage with the cam, said gear Wheel being disposed at right angles to the revoluble member, one face of the Wheel being substantially in alinement with the axis of the revoluble member, whereby the cam engages the teeth and exerts its force at right angles to the axis of the gear Wheel When r0- tating same.

In testimony whereof I aifix my signature.

HENRY J. SCHMICK.

copies of this patent may be obtained tor five cents each, by addressing the Commissioner of ratentl, Washington, D. 0. 

